The present invention relates to a process for producing packs of blades used for cutting crystal bars into wafers.
When cutting crystal bars of semiconductive or oxidic materials such as silicon, germanium, gallium arsenide, indium phosphide, sapphire, ruby or gallium gadolinium garnet, simultaneously into a plurality of wafers by means of multiple cutting processes, the grits that effect the actual abrasion of material are either brought up to on the site of the cutting in a loose state in a slurry (multiple lap cutting) or firmly bonded on the blades. In both modes of operation, a sufficient geometric precision of the cut wafers can only be ensured when the individual blades which combine to form packs of blades are aligned exactly parallel to each other.
As is known, such precise parallel alignment is ensured by inserting small spacer plates at the blade ends between the blades, and then locking such arrangement in position by pressure, for example, as described in the magazine, "Feinwerktechnik" 1962, Number 3, page 87 or by adhesives, as disclosed in German Pat. DE-AS No. 14 27 735 or the corresponding U.S. Pat. No. 3,168,087. However, since the small spacer plates must be precisely made, the production thereof is laborious and expensive. In addition, there is often the danger that the small spacer plates will tilt when inserted or clamped. The use of these conventional procedures results in losses in yield due to deficient cutting precision or mechanical damages to the workpiece such as breaking or cracking.